Display screen or portion thereof with a graphical user interface



The FIGURE is a front view of a display screen or portion thereof with agraphical user interface showing our new design.

The broken lines at the peripheries of the FIGURE illustrate a display,and the remainder of the broken lines in the FIGURE illustrate portionsof the graphical user interface. None of the broken lines form part ofthe claimed design.

CLAIM The ornamental design for a display screen or portion thereof witha graphical user interface, as shown and described.